In a printer or other similar machine, a paper cassette holding sheets of paper is installed. The sheets of paper are fed out of this paper cassette.
This kind of paper cassette comprises a case holding sheets of paper, and corner claws are attached to both sides of the front end of the case. The claws act to curl and separate the uppermost sheet of paper. Each claw has a front wall opposite to the front fringe of each sheet of paper. The uppermost sheet of paper bears on this front wall and becomes curled. When the uppermost sheet of paper is curled, the corners of the front end of the uppermost sheet of paper move diagonally toward the inside of the widthwise of the sheet and disengage from the claws. The uppermost sheet of paper is therefore fed out of the case.
However, in this conventional paper cassette, the uppermost sheet of paper fails to be disengage from the corner claws in some cases. As a result, the paper jams.
Namely the front walls of the corner claws are perpendicular to the direction in which the uppermost sheet is fed. When the uppermost sheet should be fed, the front end of the sheet bears against the front walls of the claws at right angles. Therefore, when the sheet is curled, the corners of the front end of the sheet easily slide downwardly from the position at which the front end of the paper bears on the front walls of the claws. In some cases, the corners of the front end of the sheet slip under this position and fails to be disengaged from the corner claws.
Also, the front walls of the corner claws are parallel to the front end of the sheet of paper. When the sheet is curled and the corners of the front end of the uppermost sheet move toward the inside of the widthwise of the sheet, the corner claws are strong resistance. In some cases, the corners of the front end of the sheet fails to be disengaged.